Exhaust BHP Speed - I'm "Baffled"

[Kinvig]

Right, I'm going to take the plunge & buy a new exhaust - once I've plucked up the nerve to buy a hack saw & chop the existing one up.

Not sure what I'll get yet, but loud & street legal.

Anyways this extra 3-5% bph that the manufacturers go on about - how does that affect the bike - Is it quicker acceleration? Higher top speed?

Is that normally with baffles or without?

What is a baffle & should I care about them? Do I want to remove them?

Is it easy for a muppet to put an exhaust on?

Thanks

Dirk

[Viney]

Dude, if your not a 100% in fitting your exhaust, my rates are reasonable, and live in Bromley.

The 'gain' is all subjective realy. It would be with the baffles out and with the bike fueling properly. You will notice a difference in the 4-5k region, as most cans remove this 'emmisions' flat spot.

HTH

[mattSV]

Right, I'm going to take the plunge & buy a new exhaust - once I've plucked up the nerve to buy a hack saw & chop the existing one up.

Not sure what I'll get yet, but loud & street legal.

Anyways this extra 3-5% bph that the manufacturers go on about - how does that affect the bike - Is it quicker acceleration? Higher top speed? Potentially yes to both - power in mid range will normally benefit more than top end. Fuelling may be smoother as it tends to flatten any dips in power. However 2-3 bhp increase is not that significant that it will totally transform the bike

Is that normally with baffles or without? Normally, a baffle-less can will make more power as it is less restricted than with the baffle in

What is a baffle & should I care about them? Do I want to remove them? Some cans have a removable baffle - usually a tube within the outlet - that restricts the exit flow from the can to keep the noise within legal limits. If you want more noise (and a tiny bit more power) then remove it - I have removed mine and I don't care about it :lol:

Is it easy for a muppet to put an exhaust on? Kermit would probably be allright, Gonzo's nose would get in the way. I wouldn't let Animal anywhere near it - he would only wreck it
Thanks

Dirk

HTH

[the white rabbit]

Is it easy for a muppet to put an exhaust on?


I did mine. That's your answer :lol:

[jonboy]

Anyways this extra 3-5% bph that the manufacturers go on about - how does that affect the bike - Is it quicker acceleration? Higher top speed?

It's all bull, you'll not notice any real difference, but boy will it sound great ;).


.

[the white rabbit]

Anyways this extra 3-5% bph that the manufacturers go on about - how does that affect the bike - Is it quicker acceleration? Higher top speed?

It's all bull, you'll not notice any real difference, but boy will it sound great ;).


.

There's a significant psychological increase in BHP tho, and an equivalent reduction in mental age :wink: :lol:

[jonboy]

There's a significant psychological increase in BHP tho, and an equivalent reduction in mental age :wink: :lol:

Ah,you mean PBHP? Yes, loads of it — great stuff. :lol:


.

[fizzwheel]

Anyways this extra 3-5% bph that the manufacturers go on about - how does that affect the bike - Is it quicker acceleration? Higher top speed

It made naff all difference performance wise. I found I got slightly better MPG and also it seemed to rev easier. It definatly spins the motor up a little faster with a end can on it.


Is that normally with baffles or without?

What is a baffle & should I care about them? Do I want to remove them?

Depends on the can some cans give more BHP with the baffles out. Some cans give more BHP with the baffle in. There was a test in Ride Magazine ages ago that I read about this.

A Baffle is normally a steel tube that is inserted into outlet of the exhaust it makes the exhaust quieter. I took the baffles out of my can before I put it on the bike. It makes a better noise without them in. the sound is deeper with more vtwin rumble.

Is it easy for a muppet to put an exhaust on?

I managed mine OK, it might seem daunting taking a haxsaw or angle grinder to your pipe but it really isnt difficult. Its been covered a few times if you do a search you'll get some really great tips.

HTH

[Sid Squid]

Anyways this extra 3-5% bph that the manufacturers go on about - how does that affect the bike - Is it quicker acceleration? Higher top speed?

It's all bull, you'll not notice any real difference, but boy will it sound great ;).


.

Correct. Every word a gem. There's lies, damned lies and statistics, but by far the worst utter howlers are BHP figures. Ignore - it's mostly bollox.

[Spiderman]

I took the attitude that no can is gonna make any perceptible diffrence to my speed so all i wanted after that was the "right" sound and for it to be legal.

I ended up with a G-force street legal jobby. Everyone whos ridden with me says how good it sounds and ive even been chased by a cop on a bike who thought it must be a race can. Boy was he suprised that it has a BS stamp on it.

Ok, my baffle is out but the stamp aint on the baffle so its still pretty legit for wandering eyes.

This is what i got http://www.gforceexhausts.co.uk/new_page_4.htm its the top one and i fitted it myself. Very worried but it was easier than i expected.

[valleyboy]

I found the bike revs quicker with the baffle out.... sounds mucho better as well :twisted: can be a bit worrying when you are out late on the bike, say 1 am, and you KNOW that every bugger for miles around can hear you :lol:

[kwak zzr]

engine does rev more freely with the baffle out cuz i put it back in the other day and could'nt stand how strangled it felt.

[jonboy]

I took the attitude that no can is gonna make any perceptible diffrence to my speed so all i wanted after that was the "right" sound and for it to be legal.

Perfect attitude. It's all aural aesthetics — whichever sounds best to your ears, is the one to go for.


.

[northwind]

We're talking slipons here, right? If so, yes, buy the one you like the look and sound and price of. And that's it. Anyone who argues otherwise, I shall mock :)

I like numbers :) You can feel a 5 bhp difference on an SV if you actively look for it and you have a solid comparison, but within 10 minutes you just adapt to it and it's exactly like standard, provided the curve's the same shape. You'd feel the difference between mine and a standard SV if you A/B'd them, I'm sure-certainly I do (I keep on stalling standard SVs, since mine'll pull away at silly low revs, for example) but again, 5 minutes later it'd just be assimilated.

And as far as speed, it's still massively less of an influence than the rider- I reckon almost any normal road rider would gain more overall speed, or cut more off a lap time, with a couple of hours' training than with an extra 10bhp.

But that's all irrelevant, since you won't get 5bhp from a slipon.

[Kinvig]

Cheers for the info, guys.

So, basically:

The only real difference is the noise level & a muppet could do it once he'd gotten over his fear of, "OMG I'll hacking into my bike"!

Looks like I'll be casting my eye over SV I see at trafic lights now & asking the rider to rev the throttle a bit.

I was hoping to make a mod to my bike that wasn't "cosmetic". All my bike's had done to it so far is the equalivent to furry dice & Go Faster stripes!


Still....power tools.....! Grrrreat!


p.s. Viney - cheers for the offer. I want to tackle this myself but don't leave the country - you may get a pm along the lines of, "I've just hacked off the swing arm by mistake, can you help?"! ;o)

[Spiderman]

Looks like I'll be casting my eye over SV I see at trafic lights now & asking the rider to rev the throttle a bit.


Alternatively, get yourself down to soho on a friday night, meet the soho massive and see the selcetion of cans on show there. I'm sure there is almost every single brand there most weeks. Then ask nicely (we are all open to coffee bribery btw) for the owner to fire her up and you get to hear em too. Far easier than the "traffic light shopping" you suggest. ;)

[lynw]

My insurers didnt worry about the end can declared. They only care if its a full system which is where you would probably get a bhp difference thats slightly noticeable and enough to warrant changing your insurance details. But check with your insurers they are ok with this, some policies are strictly no mods, others are more flexible.

Changing the end can didnt make that noticeable difference to me its as jonboy says, it does sound so so so much better though. :D

[the white rabbit]

Anyone who argues otherwise, I shall mock :)

Brilliant! :lol:

[northwind]

Stolen from Simon Munnery ;) And thus, I win.

[stuartyboy]

Dude,

I did mine today and it was a piece of ****.

If you do do it yourself then

1. Do NOT use a grinder unless you know what you are doing. ie mask off the tyres, swing arm etc. Sparks from a grinder can seriously mark your paintwork/seat/tyres.

2. DO make sure the exhaust pipe above the weld is COOL to the touch. Don't want to lose any skin.

3. WHEN it's cool - place a cable tie round the area you want to cut - this way you use it as a guide and will get a "square" cut and not something squew whiff

4. Use a hacksaw with a NEW blade. It will cut through like butter.

4.a Let the saw do the work - it cuts cleaner and quicker.

5 Once youve sawn it off, use a file to smooth down any burrs. VERY IMPORTANT cause if you dont then it can leave a high spot which can blow from the joint.

6. Get some silicone sealant - or if you know a mechanic then get some exhaust paste. Keep it for later.

7. DRY FIT first. This means fit it all together without screwing anything tight. This way you will be able to see how things fit together. Nothing worse than fitting it together then the paste sets and your can is out of alignment.

8. Once youve done all the above, smear the joins with sealant or paste, screw it all together, clean off excess paste and go and have a cup of tea***. Do NOT fire it up just yet - you need to let the sealant set.

***If you don't like tea then spend 15 minutes polishing the can.

9. crank it up and look for water droplets from the joints. If there's none then you're fine. If there's water blowing from the joints then you need to check its been properly sealed or tightened.

10 - If all is well then go rev the tits off it and annoy the feck out of the neighbours.

As for power increase - no idea but what I can say is the sound is horny as phuque.

I now have a dent in the tank where my lad rests ;)

[Blue_SV650S]

Race cans will generally give you a little more top end power, but will rob you power in the mid range … this is to do with back pressure and perceived exhaust length, this is exhaust tuning, you can’t get away from this I am afraid. Unless you are really lucky, after putting a can on you are only going to be able to get a ‘clean-map’ with a dyno setup. But just slipping one on it’ll run fine (just not optimal).

Like others have pointed out, I think having a race can is all about the sound, not the performance!!! 8)

As is fitting a K&N :thumright:

[northwind]

Well, on the SV there's an artificial dip in the midrange which can often be removed with a race can and jet work... Or, most likely, with a half-step shim on the needles and a standard matter. It's barely worth doing, mind, but it can avoid the usual drop in idrange that you'd expect.

With race systems, there's not a quality system for the SV that causes a midrange drop, which is nice. In fact, with the Arrow you get more in the midrange than you do on top.

[Blue_SV650S]

Has anyone ever bothered getting this flat spot jetted out with a stock can??

Its safe to say even if you get zero real performance gain, it will sound 5 times as powerful :lol:

[northwind]

Has anyone ever bothered getting this flat spot jetted out with a stock can??


Seems like a DJ half-step shim would do it... I've seen US instructions on it, but they've got slightly different setup of course.